1. Field of the Invention
The present invention relates generally to the field of signs for the control of pedestrian and vehicle traffic and more specifically to the field of signs for the control of traffic with an electronic display which can be programmed remotely to change the message which is displayed.
2. Description of the Prior Art
The field of devices which control pedestrian and vehicle traffic has been studied extensively and a number of approaches have been developed. This field is important because without clear and visible direction, collisions can occur between vehicles and between vehicles and pedestrians resulting in personal injury, loss of life, or property damage. This is especially true in high traffic areas such as construction areas and areas adjacent to schools. Even though the need to provide adequate control of traffic is well defined, the approaches to the control of pedestrian and vehicle traffic are diverse and varied.
One example is disclosed in U.S. Pat. No. 2,564,170 issued to Nusbaum, et al. This device is portable, it being mounted on wheels, with an electric signal light powered from a battery. The device achieves traffic direction through the use of a sign mounted on the support structure for the light. The light is used to attract attention to the message of the sign.
Another example is disclosed in U.S. Pat. No. 2,612,548, issued to Swanson. The device is portable and achieves traffic direction through the use of printed messages facing traffic and an electric light to attract attention to the message of the sign.
In U.S. Pat. No. 3,867,718, issued to Moe, a pair of signal-display units is used to control traffic by changing the traffic condition indication of the signal-display units. Remote control of the pair of signal-display units is achieved through the use of a radio frequency transmitter controlled by an operator and individual receivers at each signal-display unit. The units are portable.
A hinged-panel portable traffic control device is found in U.S. Pat. No. 4,226,040 issued to Carroll, et al. The device displays a single message for traffic control and is not lighted.
Another hinged-panel portable traffic control device is found in U.S. Pat. No. 4,928,415, issued to Walters. The device provides for visual messages on the faces of the hinged panels. By reversing the panels, messages which have been imprinted on the reverse side of the panels are exposed, thus providing for a change in the visual message which is displayed. The device is not lighted.
Still another hinged-panel portable traffic control device is found in U.S. Pat. No. 4,999,937, issued to Bechtold. The device can display multiple messages by manually replacing signage attached to the faces of the device. The device is not lighted.
A pedestrian crossing safety apparatus is disclosed in U.S. Pat. No. 5,023,607, issued to Staten. The device consists of a STOP message surrounded by a border of battery-operated, selectively flashing lights to direct attention to the message.
In U.S. Pat. No. 5,422,638, issued to Singer, et al., a portable traffic control sign is disclosed which consists of a sign mounted on pole which can be rotated 180 degrees between two positions. The message displayed to traffic facing the sign can be changed between the messages displayed on the respective front and back faces of the sign. An electrical cable connecting the sign to a switch unit held by the operator remotely controls the rotation of the sign. The sign is not lighted.
Another portable traffic control sign selectively displaying one of two messages is disclosed in U.S. Pat. No. 5,493,292, issued to Fanslow, et al. In this device a panel with the message to be displayed is moved to a super-imposed position overlaying the other panel containing the second message. In a one-way construction zone, a timer portion of the device alternately selects between slow and stop messages so that a pair of the devices can provide control of traffic without the presence of an operator. The sign is not lighted.
Thus, a variety of portable signs which control pedestrian and vehicle traffic is known. Most of the devices make provision for changing the traffic control message displayed by the device. However, the number and combination of messages is severely limited and in most cases difficult to select. Only one of the above-referenced devices allows an operator to remotely select the message displayed. In that case an electrical cable was required to connect a control in the hands of an operator with the portable sign to effectuate a change in displayed message.
Accordingly, it would be desirable to develop a portable traffic control sign using a highly visible electronic display which could be remotely controlled to display a number of messages as selected by an operator utilizing a remote control which does not require an electrical connection between the sign unit and the control in the hands of the operator.